A current portable device enabling High Definition Multimedia Interface (HDMI) and Universal Serial Bus (USB) data transmission function is provided with two interfaces: an HDMI interface and a USB interface, and the two kinds of signals are output via their respective transmission channels. That is, a HDMI signal is output through a standard HDMI interface (e.g., HDMI Type-A interface) whereas a USB signal is output through the USB interface (e.g., USB Type-C interface).
FIG. 1 is a signal pin definition schematic diagram of an HDMI Type-A interface. Referring to FIG. 1, the pin of the standard HDMI Type-A interface and an actual use situation are as follows: Pin 14 is a reserved pin and not in use, Pin 17 is directly grounded, so actually available signals are a total of 16 lines including three pairs of differential data (TMDS Data2+/−, TMDS Data1+/−, TMDS Data0+/−), one pair of clock (TMDS Clock+/−), two IIC signals (SCL, SDA), Hot Plug Detection (HPD) and Consumer Electronics Control (CEC) signal, power supply and grounding. A Transition Minimized Differential Signal (TMDS) is a signal transmission link in the HDMI.
FIG. 2 is a signal pin definition schematic diagram of a USB Type-C interface. Referring to FIG. 2, the signal pin of the Type-C interface is used in the following way: on a USB Type-C connector have already been defined four pairs of high-speed signals, TX1+/−, RX1+/−, TX2+/− and RX2+/− respectively, and four low-speed signals CC1, CC2, SBU1 and SBU2, wherein CC1 and CC2 are two key pins and have many functions, e.g., detect connection and distinguish positive and reverse sides, and wherein auxiliary signals SBU1 and SBU2 (Side Band Use) are only used in some specific transmission modes.
As known from the above, in the prior art if a user wants to use the HDMI function and USB function of the portable device simultaneously, he needs to insert corresponding data connection lines respectively, namely, he at least needs to perform the interface insertion operation twice, which causes inconvenience to the user and leads to undesirable user experience.
In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.